1. Field of the Invention
The present invention relates to a cable reel incorporated into a steering device of an automobile. More particularly, the present invention relates to a cable reel, the thickness of which is small, capable of rotating smoothly.
2. Description of the Related Art
Recently, there has been provided a cable reel in which a flat cable accommodating chamber formed as an annular hollow section is disposed. The annular hollow section is formed between a stationary body fixed onto a steering column side and a movable body fixed onto a steering shaft side. A flat cable is movably accommodated and inverted in the flat cable accommodating chamber, and a plurality of rollers are arranged in the annular hollow section as rotary guide members to guide the flat cable.
For example, as shown in FIG. 45, a stationary body 1, which serves as an outer cylinder and includes an outer frame 1a and a bottom plate 1b, and a movable body 2, which serves as an inner cylinder, are relatively rotatably connected with each other. A base plate 4 is rotatably set on the bottom plate 1b in the annular hollow portion 8 that is formed between the stationary body 1 and the movable body 2. A group of rollers 5 are supported by pins 4b protruded from the base plate 4. The flat cable 3 is wound around the inner circumferential passage 6 formed between the rollers 5 and the inner cylinder 2a of the movable body 2, and is also wound around the outer circumferential passage 7 formed between the rollers 5 and the outer frame 1a of the stationary body 1, while the flat cable 3 is inverted and formed into a U-shape. One end of the flat cable 3 is fixed at the stationary body 1, and the other end of the flat cable 3 is fixed at the movable body 2.
In the above cable reel, when the movable body 2 is rotated in one direction, the flat cable 3, which is inverted and formed into a U-shape, passes an inversion section formed between the rollers 5, and the flat cable 3 is wound into the inner circumferential passage 6. On the other hand, when the movable body 2 is rotated in the opposite direction, the flat cable 3 is wound back and sent out to the outer circumferential passage 7.
Compared with a cable reel in which a flat cable is spirally wound in an accommodating space, the aforementioned inversion type cable reel is advantageous in that the length of the flat cable can be reduced.
However, the following problems may be encountered in the above cable reel. In order to support the rollers 5 accommodated in the annular hollow portion 8 while leaving a space between the rollers, the base plate 4 is set being engaged with a groove 1c formed on the bottom plate 1b. Therefore, thickness of the bottom plate 1b is increased. Accordingly, the overall height H of the cable reel is increased, which makes the cable reel size large.
Further, since the pins 4b for holding rollers 5 are protruded from the base plate 4 at predetermined positions, the structure becomes complicated and the size of the cable reel is increased, and further the material cost is raised. Furthermore, in the case where a bolt rotatably penetrates the axial center of each roller so as to prevent the roller from coming out, the number of parts and the number of working steps are increased corresponding to the number of rollers.
Also, the following problems may be encountered. Since gap S exists between an upper end of the rollers 5 and a roof face 1a-1 of the outer frame 1a, the roller 5 rattles and vibrates in the vertical direction. At the same time, the roller collides with the roof face 1a-1 and noise is generated.
In order to prevent an increase of the collision sound, it is preferable that gap S is decreased. Therefore, the height of the roller 5 cannot be reduced too low compared with the height of the annular hollow portion 8. Accordingly, it is impossible to reduce the size and weight of the roller.
The present invention has been accomplished to solve the above problems.
An object of the present invention is to provide a cable reel having an improved roller supporting mechanism so as to reduce the costs of parts and the number of working steps. The cable reel has a small thickness and lower rotating torque.
In order to solve the above problems, the present invention provides a cable reel comprising: a cylindrical stationary body and a movable body combined with each other to define an outer cylindrical section, inner cylindrical section, bottom plate section and roof plate section surrounding an annular hollow section; a guide member disposed in the annular hollow section, the guide member including a C-shaped ring and a plurality of rollers spaced apart from each other and rotatably supported by the ring; a flat cable having one end fixed at the movable body and the other end fixed at the stationary body, the flat cable wound round an inner circumferential passage formed between the inner cylindrical section and the rollers and wound round an outer circumferential passage formed between the outer cylindrical section and the rollers, wherein a winding direction of the flat cable in the inner circumferential passage is inverted to that of the flat cable in the outer circumferential passage; an intermediate portion of each roller is rotatably held by the ring under the condition that a roller axis is tilted; and at least one portion of each roller on the inner cylindrical section side comes into contact with the flat cable passing through the inner circumferential passage and at least one portion of each roller on the outer cylindrical section side comes into contact with the bottom plate section of the stationary body.
When the cable reel is composed as described above, the ring for holding the rollers is not arranged in a lower portion of the rollers but arranged in an intermediate portion of the rollers, which is unlike the conventional structure. Therefore, thickness of the guide member for guiding the flat cable becomes the same thickness as the thickness (height) of the rollers. Accordingly, the thickness of a product can be reduced.
When each roller is tilted, the inner cylindrical section side of the roller comes into contact with the flat cable which is a rotating object, and the outer cylindrical section side of the roller comes into contact with the stationary body which is a fixed object. Therefore, the above two contact positions are symmetrical to each other with respect to the rotary axis. Accordingly, the roller can be smoothly, stably rotated, and it becomes possible to reduce frictional resistance caused between the stationary body and the rollers. At the same time, irregular fluctuation of torque can be reduced.
The present invention provides a cable reel in which the ring has bearing holes arranged at predetermined intervals in the circumferential direction, the roller is formed into a bobbin-shape in which an annular recess portion at an intermediate portion in the axial direction of the roller is interposed between an upper and a lower large diameter portion, the annular recess portion of the roller is rotatably engaged in the bearing hole of the ring, a lower end portion of the roller on the outer cylindrical section side comes into contact with the bottom plate section under the condition that the inner cylindrical section side of the roller is raised from the bottom plate section, and the inner cylindrical section side of the roller comes into contact with the flat cable.
When the shape of each roller and the shape of the ring for holding the rollers are formed as described above, the rollers can be attached to the ring only by inserting the annular recess portion of each roller into the bearing hole of the ring. Due to the above structure, it becomes unnecessary to provide pins, which are conventionally used and protruded to hold the rollers. Further, it becomes unnecessary for the rollers to be fastened by bolts. Accordingly, the number of parts and the number of working steps can be reduced.
When the axial line of each roller is tilted, only the outer cylindrical section side of the lower end face of each roller comes into point-contact with the bottom plate section while the inner cylindrical section side of the lower end face of each roller is rising from the bottom plate. Accordingly, it is possible to decrease a contact area of the bottom plate section with the rollers, which enables to greatly reduce contact friction.
The present invention provides a cable reel in which the axis of the roller is tilted to the outer cylindrical section side by the tilting angle of not less than 3xc2x0 and not more than 20xc2x0 with respect to the normal line of the bottom plate section.
The tilting angle range is determined as described above for the following reasons. When the tilting angle is too large, height and width of the roller are increased. When the tilting angle is too small, the contact area of the bottom plate section with the roller is increased, which excessively increases a frictional force.
It is preferable that one portion of each roller is made to come into contact with the roof section of the movable body.
When one portion of each roller is made to come into contact with the roof section as described above, each roller is interposed between the top and the bottom. Therefore, no rattle is caused in the vertical direction and the generation of noise can be prevented.
Since each roller is tilted, a contact position of the roof plate with the roller is located at the inner cylindrical section side. Since the inner cylindrical section side of the roller comes into contact with the flat cable which is a rotating object, the roller can be stably rotated if the movable body, which is a rotating body in the same manner, is made to come into contact with the upper portion of the roller.
It is preferable that a groove is formed at least one of the bottom plate section and the roof plate section, and an edge portion of the roller is rotatably inserted into and engaged with the groove. It is preferable that the groove is formed on the bottom plate so that the roller can be surely contacted with the bottom plate. In the case where the roller is also contacted with the roof plate, the groove may be also formed on the roof plate. In this connection, of course, the grooves may be formed on both the bottom plate and the roof plate.
When the groove is formed on the bottom plate or roof plate as described above and a lower end edge of the roller on the outer cylindrical section side or an upper end edge of the roller on the inner cylindrical section side is inserted into the groove, the above roller and ring are not idly moved in the annular hollow section in the radial direction. Therefore, it is possible to prevent the occurrence of rattle and noise, and the roller and the stationary body positively come into contact with each other, and the rollers can be stably rotated.
An upper and a lower large diameter portion interposing the annular recess portion may be formed into a cone-shape, the diameter of which is reduced downward, and the inner cylindrical section side of the upper and the lower large diameter portion of the roller may come into line-contact with the flat cable passing through the inner circumferential passage while the inner cylindrical section side of the upper and the lower large diameter portion is kept parallel with the inner cylindrical section.
The flat cable accommodated in the annular hollow section being wound in an inversion state can be easily extended in the outer circumferential direction (diameter expanding direction) by its rigidity.
Therefore, as described above, when outer faces of the upper and the lower large diameter portion of the roller, the axis of which is tilted, are inclined being formed into a conical shape, while the circumferential faces on the inner cylindrical section side of the upper and the lower large diameter portion are kept parallel with the axis of the inner cylindrical section (that is, the circumferential faces on the inner cylindrical section side of the upper and the lower large diameter portion are kept in the normal line direction of the bottom plate), the roller is made to come into not point-contact but line-contact with the upper and the lower side portion in the width direction (height direction) of the flat cable in the inner circumferential passage. Due to the foregoing, it is possible to prevent the flat cable from expanding in the outer circumferential direction.
A spring may be protruded from an outside circumferential edge of the bearing hole provided in the ring, and the outer cylindrical section side of the lower large diameter portion of the roller may be pushed downward by the spring.
When the spring is provided as described above, it becomes possible to reduce the occurrence of rattle between the rollers and the ring, and further it is possible to suppress the occurrence of rattle between the bottom plate and the sliding section. Accordingly, the roller can be smoothly rotated, and the occurrence of noise can be prevented.
A slit may be formed in an outer circumferential edge of the bearing hole provided in the ring.
When the above slit is provided, the periphery of the bearing hole can be easily bent. Therefore, even when the roller is pinched by the movable body and stationary body in the vertical direction, the bearing hole is bent, so that the tilting angle can be changed. As a result, the roller height is flexibly changed. Therefore, the roller and ring can be accommodated in the annular hollow section without being damaged.
The bearing hole of the roller formed in the above ring is formed being communicated with a cut-out groove which is formed being cut out at the inner circumferential edge or outer circumferential edge of the ring, and the annular recess portion of the roller is attached from the side portion while it is made to pass through the cut-out groove. When the above structure is adopted, the roller can be attached into the bearing hole of the ring by one-touch motion.
In this connection, the roller may be split into two, and the thus split pieces of the roller may be incorporated into the bearing hole, which is formed penetrating the ring, from the top and the bottom.
The present invention provides a cable reel comprising: a cylindrical stationary body and a movable body combined with each other to define an outer cylindrical section, inner cylindrical section, bottom plate section and roof plate section surrounding an annular hollow section; a guide member disposed in the annular hollow section, the guide member including a C-shaped ring and a plurality of rollers spaced apart from each other and rotatably supported by the ring; and a flat cable having one end fixed at the movable body and the other end fixed at the stationary body, the flat cable wound round an inner circumferential passage formed between the inner cylindrical section and the rollers and wound round an outer circumferential passage formed between the outer cylindrical section and the rollers, wherein a winding direction of the flat cable in the inner circumferential passage is inverted to that of the flat cable in the outer circumferential passage; each roller has a conical shaft portion between an upper and a lower large diameter portions, the outer diameters of which are different from each other; an inner circumferential face of each bearing hole formed in the ring in the circumferential direction at regular intervals is tapered to be engaged with a conical shaft portion of the roller; and an upper and a lower attaching position of the roller are restricted with respect to the bearing hole of the ring.
When the cable reel is composed as described above, the ring for holding the rollers are not arranged in a lower portion of the rollers but arranged in an intermediate portion of the rollers, which is unlike the conventional structure. Therefore, thickness of the guide member for guiding the flat cable becomes the same thickness as the thickness of the rollers. Accordingly, the thickness of a product can be reduced.
Further, the intermediate shaft is provided in the roller and supported in the bearing hole of the ring. Therefore, it is unnecessary to protrude a pin for holding the roller like the conventional structure, and further it is unnecessary to fasten the roller with a bolt. Accordingly, the number of parts can be reduced, and the number of working steps required for attaching work can be reduced.
The above roller has the upper and the lower large diameter portions. Further, the outer diameter of the roller is changed, and a contact position of the roller outer circumferential face with the bottom plate and/or roof plate and a contact position of the roller outer circumferential face with the flat cable are set.
Therefore, when positions of the upper and the lower large diameter portions with respect to the ring are turned upside down, the roller does not come into contact with the flat cable at a predetermined position, which might cause damage on the flat cable.
On the other hand, as described above, when the bearing hole of the ring and the intermediate shaft of the roller are tapered and engaged with each other, the upper and the lower position of the roller can be restricted. If a worker mistakes the assembling direction of the roller, it is impossible to engage the roller with the bearing hole. Accordingly, it is possible to prevent the roller from being attached upside down.
The above roller may be of the one body type. Alternatively, the above roller may be divided into an upper member and a lower member, that is, the above roller may be composed of two members.
In the case where the roller is divided into the upper member and the lower member, a conical shaft section, the diameter of which is reduced toward a forward end portion, is protruded from one end face of one of the rollers, an engaging pawl is protruded from a forward end outer circumferential face of the conical shaft section, and the other roller is formed into a cylindrical shape and an engaging hole is formed at the center of a bottom face.
When the roller is divided into the upper and the lower roller as described above, it becomes possible to assemble the rollers from an upper and a lower position while the bearing hole in the ring is formed into a through-hole.
Instead of the structure in which the conical shaft is provided in the roller and the bearing hole is tapered, a stopper section may be protruded upward or downward from an outer circumferential edge of the ring in the radial direction from the bearing hole, and when a vertical position of the roller is not normal, it becomes impossible to assemble the roller because the roller on the large diameter side interferes with the stopper section, so that the vertical attaching positions of the rollers are restricted with respect to the ring.
In this case, the shaft protruding from one of the rollers may have the same diameter, and it is unnecessary to make the bearing hole to be tapered.
In any case of the one body type roller or the split type roller, a diameter of the upper large diameter portion is larger than that of the lower large diameter portion, outer circumferential faces of the upper and the lower large diameter portion are tapered, when the roller is assembled to the ring, an axis of the roller is tilted so that a lower end edge on the outer cylindrical section side of the lower large diameter portion comes into contact with the bottom plate and the inner cylindrical section side is raised from the bottom plate and further outer circumferential faces on the inner cylindrical section side of the upper and the lower large diameter portion become parallel with the inner cylindrical section and come into line-contact with an upper and a lower side of the flat cable passing through the inner circumferential passage.
When each roller is tilted, the inner cylindrical section side of the roller comes into contact with the flat cable which is a rotating object, and the outer cylindrical section side of the roller comes into contact with the bottom plate of the stationary body. Therefore, the above two contact positions are symmetrical to each other with respect to the rotary axis. Accordingly, the roller can be smoothly, stably rotated, and it becomes possible to reduce frictional resistance caused between the stationary body and the rollers. At the same time, irregular fluctuation of torque can be reduced.
A lower end face of each roller at a lower end edge on the outer cylindrical section side comes into point-contact with the bottom plate section while a lower end face of each roller on the inner cylindrical section side is rising from a bottom plate. Accordingly, it is possible to decrease a contact area of the bottom plate section with the rollers, which enables to greatly reduce contact friction.
It is preferable that lubricant is coated on the bottom plate or a sliding sheet is stuck on the bottom plate so as to reduce sliding friction between the bottom plate and the roller.
A tilting angle of the roller axis is tilted toward the outer cylindrical section side by an angle in the angle range nor less than 3xc2x0 and not more than 20xc2x0 with respect to the normal line of the bottom plate.
The reason why the tilting angle of the roller axis is set in the above angle range is described as follows. When the tilting angle is too large, the height and width of the roller are increased. When the tilting angle is too small, a contact area of the roller with the bottom plate is extended, and an intensity of frictional force is increased too high.
It is preferable that an upper end edge on the inner cylindrical section side of the upper large diameter portion of each roller is made to come into contact with the roof section composed of the movable body.
When one portion of each roller is made to come into contact with the roof section as described above, each roller is interposed between the top and the bottom. Therefore, no rattle is caused in the vertical direction and generation of noise can be prevented.
When the axis of each roller is tilted, and the outer circumferential faces of the upper and the lower large diameter portions are tapered, the inner cylindrical section side portions of the upper and the lower large diameter portions can be made to be parallel with the inner cylindrical section and come into line-contact with the flat cable.
The flat cable, which is wound in an inverse state and accommodated in the annular hollow section, is easily extended in the outer circumferential direction (diameter expanding direction) due to the rigidity.
Therefore, when the upper and the lower large diameter portions of the roller are made to come into not point-contact but line-contact with the upper and the lower side portions in the width direction (height direction) of the flat cable, it becomes possible to prevent the flat cable from expanding in the outer circumferential direction.
When a thick section is provided in the periphery of each bearing hole formed in the ring and when an upper and a lower face of the thick section are contacted with opposing faces of the upper and the lower large diameter portions, the occurrence of rattle between the ring and the roller can be prevented.
It is preferable that a groove is formed at at least one of the bottom plate section and the roof plate section, and an edge portion of the roller is rotatably inserted into and engaged with the groove. It is preferable that the groove is formed on the bottom plate so that the roller can be surely contacted with the bottom plate. In the case where the roller is also contacted with the roof plate, the groove may be also formed on the roof plate. In this connection, of course, the grooves may be formed on both the bottom plate and the roof plate.
When the groove is formed on the bottom plate or roof plate as described above and a lower end edge of the roller on the outer cylindrical section side or an upper end edge of the roller on the inner cylinder side is inserted into the groove, the above roller and ring are not idly moved in the annular hollow section in the radial direction. Therefore, it is possible to prevent the occurrence of rattle and noise, and the roller and the stationary body positively come into contact with each other, and the rollers can be stably rotated.
The present invention provides a cable reel comprising: a stationary body and a movable body combined with each other to define an outer cylindrical section, inner cylindrical section, bottom plate section and roof plate section surrounding an annular hollow section; a guide member disposed in the annular hollow section, the guide member including a C-shaped ring and a plurality of rollers spaced apart from each other and rotatably supported by the ring; and a flat cable having one end fixed at the movable body and the other end fixed at the stationary body, the flat cable wound round an inner circumferential passage formed between the inner cylindrical section and the rollers and wound round an outer circumferential passage formed between the outer cylindrical section and the rollers, wherein a winding direction of the flat cable in the inner circumferential passage is inverted to that of the flat cable in the outer circumferential passage; the ring rotatably holds an intermediate portion of each roller, height of each roller in the axial direction is changed, some of the rollers are tall rollers, the height in the axial direction of which is large, so that the upper and the lower end portions of the rollers can be contacted with the bottom plate section and the roof plate section, the other rollers are short rollers, the height of which is smaller than that of the tall rollers, so that the upper and the lower end portions of the short rollers can not be contacted with the bottom plate section and the roof plate section, and at least one portion of the short roller on the inner cylindrical section side comes into contact with the flat cable passing through the inner circumferential passage.
The ring holds the tall roller so that the axis of the tall roller on the roof side can be tilted to the outer cylindrical section side with respect to the normal line of the bottom plate and an upper end edge of the tall roller on the inner cylindrical section side can be contacted with the roof plate and further a lower end edge of the tall roller on the outer cylindrical section side can be contacted with the bottom plate.
Alternatively, the tall roller is not tilted, and an upper end of the tall roller is slidably contacted with the roof plate and further a lower end is slidably contacted with the bottom plate via a sliding sheet or sliding material.
When the above structure is adopted, unlike the conventional structure, the ring for holding the roller is not arranged below the roller but arranged in an intermediate portion of the roller. Therefore, the thickness of the guide member for guiding the flat cable is determined only by the thickness of the roller. Therefore, the thickness of a product can be reduced.
Concerning the roller, the high and the short roller are provided. Only the tall roller is contacted with the bottom plate and roof plate, and the guide member is arranged in the annular hollow section. On the other hand, the short roller is not contacted with the bottom plate and roof plate but contacted with only the flat cable. Therefore, the short roller is not given a contact frictional resistance caused by the contact with the bottom plate, which is fixed, that is, the short roller can be smoothly rotated by the contact with the flat cable. Since the short roller is smoothly rotated, the torque required for rotating the flat cable can be reduced.
The short roller may be attached to the ring being tilted, and either the upper edge or the lower edge of the outer circumference of the short roller may be contacted with the flat cable. However, when the short roller is attached to the ring not being tilted but contacted with the flat cable by the entire height of the roller, the short roller can be stably rotated.
Since the short roller is not contacted with the bottom plate and roof plate, sliding noise, which is generated by the contact with the bottom plate and roof plate, is not generated from the short roller while it is rotating. Further, since the upper and lower edges of the tall roller are contacted with the bottom plate and roof plate, rattle of the guide member is not caused in the vertical direction. Further, the occurrence of noise can be prevented.
Two tall rollers are arranged symmetrically to each other with respect to the central axis of the annular hollow section, and the lower rollers are arranged between the tall rollers at regular intervals.
Since the tall roller is provided for stably supporting the guide member in the annular hollow section, at least two tall rollers may be arranged symmetrically to each other. It is preferable that the other groups of rollers are formed into the short rollers, which are contacted with the flat cable so as to guide the rotation of the flat cable.
The tall roller is tilted so that the height of tall roller can be a little larger than the height of the annular hollow section, and when the tall roller is accommodated in the annular hollow section, the ring is twisted due to the contact of the tall roller with the bottom plate and roof plate, so that the tall roller can be tilted by an angle gentler than the tilting angle of the roller before it is accommodated.
When the above structure is adopted, the ring is twisted by an appropriate angle due to the correlation between the height of the tall roller and the height of the annular hollow section, which enhances the application of the ring. Since the tall roller is elastically restricted from the top and the bottom, it can be stably rotated without causing any rattle, and it becomes possible to flexibly accommodate the guide member without being damaged.
A slit may be formed in the outer circumferential edge of the bearing hole used for the tall roller arranged in the ring.
When the above slit is provided, the periphery of the bearing hole can be easily bent. Therefore, the tall roller can be easily twisted so that the tilting angle of the tall roller can be an appropriate value.
The roller is formed into a bobbin-shape in which an annular recess portion of an intermediate portion in the axial direction of the roller is interposed between an upper and a lower large diameter portion, a roller insertion passage communicating with the bearing hole and open to the inner circumferential edge or outer circumferential edge is formed in the ring, and the annular recess portion of the roller is rotatably engaged with the bearing hole through the roller insertion passage.
When the above structure is adopted, the roller can be attached to the ring by one-touch motion. Therefore, the assembling property can be enhanced.
In this connection, the above roller may be divided into an upper and a lower roller at a position of the intermediate annular recess portion, and the bearing hole of the ring is formed into a through-hole. The upper and the lower roller may be incorporated into the bearing hole from both sides of the top and bottom and fixed being locked.
A spring section may be protruded from the circumferential edge of the bearing hole of each roller provided in the ring, and the upper and the lower large diameter portion of the rollers may be pushed to the bottom plate contact side and the roof plate contact side by the spring section.
When the above spring section is provided, it is possible to prevent the occurrence of rattle between the tall roller and the bottom and roof plates. Further, it is possible to prevent the occurrence of rattle between the lower roller and the ring.
The present invention provides a cable reel comprising: a stationary body and a movable body combined with each other to define an outer cylindrical section, inner cylindrical section, bottom plate section and roof plate section surrounding an annular hollow section; a guide member disposed in the annular hollow section, the guide member including a C-shaped ring and a plurality of rollers spaced apart from each other and rotatably supported by the ring; and a flat cable having one end fixed at the movable body and the other end fixed at the stationary body, the flat cable wound round an inner circumferential passage formed between the inner cylindrical section and the rollers and wound round an outer circumferential passage formed between the outer cylindrical section and the rollers, wherein a winding direction of the flat cable in the inner circumferential passage is inverted to that of the flat cable in the outer circumferential passage; a roller attaching section is arranged in the ring in the circumferential direction at intervals; an upper roller, which comes into contact with a roof plate section of the annular hollow section and does not come into contact with a bottom plate section, is attached to the roller attaching section; a lower roller, which comes into contact with the bottom plate section of the annular hollow section and does not come into contact with the roof plate section, is attached to the roller attaching section; and at least one portion of the upper and lower rollers is made to come into contact with the flat cable passing through the inner circumferential passage.
When the above structure is adopted, the upper roller of the guide member comes into contact with the roof plate section (roof face) of the annular hollow section, and the lower roller of the guide member comes into contact with the bottom plate section (bottom face) of the annular hollow section. Therefore, the guide member is interposed between the top and the bottom. Accordingly, rattle of the roller is not caused in the vertical direction, and the occurrence of noise can be prevented.
Unlike the conventional structure in which the ring for holding the upper and the lower roller is arranged on the bottom face of the annular hollow section below the rollers, the ring is arranged in a central space of the annular hollow section at the intermediate portion between the upper and the lower roller. Accordingly, the thickness of the bottom plate is not increased, and the thickness of a cable reel product can be reduced.
Further, according to the conventional structure, the roller height is a little smaller than the height of the annular hollow section. On the other hand, according to the present invention, the height of the upper roller and that of the lower roller are reduced and the size of the cable reel is reduced in such a manner that a big space is formed between the upper roller and the bottom face and further a big space is formed between the lower roller and the roof face. Accordingly, the weight of the cable reel can be reduced.
When the guide member does not rattle, it becomes possible to form a big space in the lower portion of the upper roller and also it becomes possible to form a big space in the upper portion of the lower roller. Therefore, the height of the upper roller and that of the lower roller are substantially reduced to ⅔ of the height of the annular hollow section. Due to the foregoing, the roller can be downsized, and the weight of a cable reel product can be reduced.
The shape of the upper roller and that of the lower roller are identical with each other, and the height of the roller is substantially not more than ⅔ of the height of the annular hollow section.
It is preferable that the upper and the lower roller are alternately arranged upside down. When the upper and the lower roller are alternately arranged, the guide member can be stably positioned in the vertical direction.
Step portions are provided on the ring in the circumferential direction, the upper roller is attached to the roller attaching section provided in the upper step portion, and the lower roller is attached to the roller attaching section provided in the lower step portion.
Since a required height of the upper roller is the distance from the roof face to the ring (roller attaching direction) and a required height of the lower roller is the distance from the bottom face to the ring (roller attaching direction), when a step portion is provided in the ring, the above distances can be decreased irrespective of the height of the annular hollow section. Further, the roller can be downsized.
The upper and lower rollers are formed into a shape in which an annular recess portion is provided between the upper and the lower large diameter portion, the height on one side of the upper and lower large diameter portions is large so that the roller can come into contact with the roof face or bottom face, the height of the other side is small so that a space can be formed between the roller and the roof face or bottom face, a bearing hole is formed as a roller attaching section of the ring, and the annular recess portion is rotatably inserted and attached into the bearing hole.
When the above structure is adopted, the roller attaching section is simply composed in such a manner that holes are formed in the ring, and the annular recess portion of each roller is engaged in the bearing hole and prevented from coming out the bearing hole. Therefore, the guide member can be easily handled and more positively incorporated into the annular hollow section.
In this connection, concerning the method of preventing the roller from coming out, it is a conventional method that the roller is fastened by a bolt. However, when the above structure is adopted, it is unnecessary to use the above specific parts. Therefore, the number of parts can be reduced, and further the number of mandays for attaching can be also reduced.
The bearing hole formed in the ring is formed being communicated with the cutout groove which is cut out from the inner circumferential end or outer circumferential end of the ring, and the annular recess portion of the roller is attached into the bearing hole from the side through the cutout groove. In this way, the roller can be attached to the bearing hole by one-touch motion.
On the other hand, when the roller is divided into two rollers, the thus divided two rollers are respectively incorporated into the bearing hole formed in the ring from the top and the bottom. In this way, the structure of incorporating the roller into the ring can be simplified, in which only the bearing holes are formed in the ring.
The roller attaching section of the ring is formed into a support shaft protruding from an upper and a lower face of the ring, the upper and the lower roller are formed into a shape in which a bearing hole open to the roller attaching side is provided, and the support shaft of the roller attaching section is rotatably engaged in the bearing hole.
When the above structure is adopted, only when the support shafts of the ring are inserted into the bearing holes of the upper and the lower roller, the rollers can be held. Therefore, it becomes unnecessary that the height of the upper roller is set at the distance from the roof plate to the ring, and also it becomes unnecessary that the height of the lower roller is set at the distance from the bottom plate to the ring. Accordingly, the cable reel can be downsized and further the weigh of the cable reel can be reduced.
The upper and the lower roller are attached to the ring while the axis of the roller is being tilted, and edges of the upper and the lower face of the upper and the lower roller are respectively contacted with the roof face and the bottom face. Then, the contact portion is put into a point contact condition. Therefore, it is possible to reduce a contact area of the roof face with the upper roller, and also it is possible to reduce a contact area of the bottom face with the lower roller. Accordingly, the friction of contact can be greatly reduced. As a result, the flat cable slidably coming into contact with the upper and the lower roller can be smoothly rotated.
The roof face and the bottom face are formed into a portion of the stationary body, the axis of the roller coming into contact with the roof face is tilted from the bottom face in the upper inner direction, and the axis of the roller coming into contact with the bottom face is tilted in the upper outer direction, so that an outer cylinder side edge of the roller comes into contact with the roof face or the bottom face.
When the roller is tilted in the above direction, the inner cylinder side of the roller comes into contact with the flat cable which is a rotary body, and the outer cylinder side of the roller comes into contact with the roof face or bottom face which is a stationary body. That is, the above two contact positions become symmetrical to each other with respect to the axis. Therefore, the roller can be smoothly and stably rotated, and further frictional resistance of the stationary body with the roller can be reduced and furthermore irregular fluctuation of torque can be reduced.
In this connection, in the case where the roller is simultaneously contacted with the bottom and the roof face, the lower outer edge of the roller comes into contact with the bottom face, and the lower inner edge of the roller comes into contact with the flat cable. Therefore, the upper end inner edge of the roller comes into contact with the roof face. In this case, the upper end inner edge and the lower end inner edge are located on the same side with respect to the roller axis. Therefore, the roof face must be a movable body which is the same rotary body as the flat cable. However, according to the present invention, the upper roller does not come into contact with the bottom face. Therefore, the present invention can be preferably applied to a case in which the roof face is a stationary body.
In this connection, the axes of the upper and the lower roller may not be tilted but the axes may be made perpendicular to the roof and the bottom face, and one end face of the upper roller and that of the lower roller may be respectively made to come into surface-contact with the roof face or the bottom face. In this case, it is preferable that the roof and the bottom face are coated with lubricant or covered with a sliding sheet so that the sliding friction with the upper and the lower roller can be reduced.